| Accelerating rate calorimeter is an important scientific instrument applied in reaction thermal safety assessment,it simulates the adiabatic thermal runaway process of the sample and records temperature data and pressure data to solve the kinetic and reaction thermodynamics parameters,then estimates the important index of chemical process thermal hazard,therefore can carry out chemical production in safety by guarantee.This paper comprehensively analyzed the present situation of adiabatic reaction heat metering methods and accelerating rate calorimeter,for the phenomenon of thermal absorption in reaction system caused reaction path deviating from the ideal adiabatic process problem,proposed power compensation adiabatic reaction heat metering methods,and provided real-time power compensation to reaction system by two-grades adiabatic structure and it's temperature control strategy and control algorithm,in addition,completed instrument design.Firstly,this paper carried out power compensation technology scheme design.On structure,designed first-grade adiabatic furnace and second-grade power compensation unit.Meanwhile,designed measurement and control system in hardware and programming framework to meet instrument indicators which can be the carrier of the logic and algorithm of temperature control,also compiled monitoring system software to improving the efficiency of instrument development and debugging.In order to achieve the uniformity of the temperature field of the first-grade adiabatic furnace,the simulation and design of the furnace temperature field were carried out by using the finite element method.It can further eliminate the heat sink effect of reaction system by the second-grade power compensation unit,in the same time analyze it's mechanism from the angle of heat transfer,and the we can study the control strategy of power compensation by using dynamic heat transfer model of reaction process.Using feed-forward compensation and fuzzy control algorithm based on PID control,the temperature control logic of "heat-wait-search" and dynamic temperature tracking of reaction process is realized.Further we proposed the temperature difference baseline correction method in the process of tracking temperature control to solve the practical engineering problems such as temperature measurement drift,and then can improve the adiabatic control performance.In finally,the control effect was tested by constant temperature experiment,the temperature control precision of first-grade adiabatic furnace and second-grade power compensation unit reached a high level.The effectiveness of the power compensation strategy is verified by using the power compensation accelerating rate calorimeter and traditional accelerating rate calorimeter carrying sample test,the results showed that it can guarantee the reaction is going to be closer to the ideal adiabatic environment.Multi sample repeatability experiments were designed to test the performance reliability of the instrument,and results proved that it had good repeatability. |
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